Coupling Analysis of Differential Power Processing-Based PV System and Its Decoupling Implementation of Synchronous MPPT Control

Abstract

Differential power processing (DPP) is considered to be a highly competitive architecture for photovoltaic (PV) applications due to its characteristics, such as high energy efficiency and mitigation of mismatch issues. However, the complexity of coupling between DPP converters poses challenges in terms of maximum power point tracking (MPPT) in DPP-based PV systems. To address the disadvantage of the asynchronous MPPT commonly used in existing DPP topologies, which is inefficient and difficult to extend to large-scale systems, this paper presents a method that makes the application of synchronous MPPT in DPP topology feasible based on a simple and easy partial decoupling method. The innovation of the proposed decoupling method is that the dominant part of the system coupling is obtained by decomposition of the control system, to facilitate more targeted decoupling and reduce the difficulty and complexity of decoupling. Unlike other decoupling methods, the proposed approach does not become more complex with an increase in the size of the system, and thus has good scalability. In addition, the efficiency of MPPT is improved, as synchronous MPPT control can significantly reduce the MPPT time of the PV system. The results of simulations and experiments validate the effectiveness of the proposed decoupling method and the high performance of synchronous MPPT in DPP-based PV systems.